Skip to content
GH SecretagogueWADA ProhibitedCompare

GHRP-6

Also known as: Growth Hormone Releasing Peptide 6, Growth Hormone Releasing Hexapeptide, SK&F 110679

4
1 · Natty510 · Enhanced

Lower numbers = closer to natural. Higher numbers = more enhanced.

Why this rating?

Per Pandya et al. 1998, GHRP-6 alone produces a peak GH increase of ~33.8 μg/L, which falls to ~6.2 μg/L when endogenous GHRH is blocked with a GHRH antagonist. Demonstrating that GHRP-6 requires endogenous GHRH for its full effect and works through natural pathways. Higher cortisol and prolactin elevation than GHRP-2. Does not affect HPT axis and requires no PCT. Rated 4 as it enhances natural GH through receptor stimulation.

Overview

A synthetic hexapeptide ghrelin mimetic that was one of the first GH secretagogues developed. Stimulates growth hormone release through the GHS-R1a receptor. Known for causing intense appetite stimulation (the "hunger peptide"), which can be beneficial for bulking but problematic for cutting. Less selective than GHRP-2 with higher cortisol and prolactin elevation.

Important Warnings

  • •Intense appetite stimulation can sabotage cutting/dieting goals
  • •Must be administered on empty stomach - food blunts GH release
  • •Less selective than GHRP-2 or Ipamorelin (more cortisol/prolactin)
  • •Research chemical status means quality varies between sources
  • •Requires endogenous GHRH for maximal effect
  • •Requires proper reconstitution and refrigerated storage

Purpose & Use Cases

Growth Hormone Release

Potent GH secretagogue reported to reach slightly higher peak GH levels than GHRP-2, though it is less potent per unit dose.

Appetite Stimulation

Intensely stimulates appetite within 20-30 minutes of injection - beneficial for hard gainers and bulking phases.

Recovery Enhancement

Elevated GH levels improve recovery from training and injury.

Body Composition

GH elevation promotes fat loss and lean mass gain, though appetite increase must be managed.

Benefits

  • Slightly higher peak GH levels than GHRP-2
  • Powerful appetite stimulation for bulking/hard gainers
  • Lower receptor affinity than hexarelin means slower/milder desensitization at standard saturation doses
  • Synergistic when combined with GHRH peptides
  • Well-studied with extensive research data
  • Longer half-life than GHRP-2 (2.5 hours vs 33 minutes)

Good to Know

The 'hunger peptide'

GHRP-6's defining trait is intense appetite stimulation within 20-30 minutes of injection, via central ghrelin-receptor activation. This makes it useful for hard-gainers and bulking but a poor fit for cutting, where GHRP-2 or Ipamorelin are cleaner choices.

Least selective GHRP: highest cortisol and prolactin

Of the common GHRPs, GHRP-6 raises cortisol/ACTH and prolactin the most (more than GHRP-2, far more than the essentially neutral Ipamorelin). Chronic elevation can contribute to fatigue and, via prolactin, reduced libido. The key reason it is considered the least clean option.

A GHRP: stimulates your own GH

It binds GHS-R1a to trigger pulsatile GH release and a downstream IGF-1 rise; it does not replace GH and does not suppress the testosterone axis. It also requires endogenous GHRH to reach its full GH-releasing potential.

GHRP-6 was the reference compound behind MK-677

Merck's discovery paper for the oral secretagogue MK-677 (Ibutamoren) describes it as "mechanistically indistinguishable from" GHRP-6 (Patchett et al., PNAS 1995). MK-677 is chemically a non-peptide, but GHRP-6 was the pharmacological template that guided its development, which is why both share the same ghrelin-receptor-driven GH release plus hunger and water-retention side effects.

100mcg saturation dose, fasted, no PCT

Roughly 100mcg (about 1mcg/kg) saturates the receptors; more frequent dosing beats larger doses. Inject on an empty stomach since food blunts the GH pulse. No PCT is ever required.

Dosage Guidelines

Experience LevelDosage Range
Beginner100 – 100 mcg/day
Intermediate200 – 300 mcg/day
Advanced300 – 600 mcg/day
Frequency
2-4x daily on an empty stomach (e.g. morning, post-workout, bedtime), each dose ~100mcg. Beginners often start with a single daily dose to gauge appetite/prolactin response before adding more.
Typical Cycle Length
4 – 12 weeks
Notes

Community/self-administered protocol, not a clinically-studied chronic regimen, the pharmacology studies used single IV bolus doses (Pandya et al. dosed 1 mcg/kg; Cabrales et al. used 100-400 mcg/kg for PK). ~100mcg per injection is the widely-cited saturation dose that fully occupies GHS receptors, so users add MORE doses per day rather than a bigger single dose once past ~100-150mcg/injection (diminishing returns per shot). These ranges are the resulting daily totals: beginner = 100mcg once daily, typical = ~100mcg x2-3, advanced = ~100-200mcg x3 (3-4 injections spaced through the day). Must be administered on an empty stomach; space doses at least 3-4 hours apart.

Side Effects

Intense Appetite Increase

very common
Severity
2.5/5

Pronounced hunger within 20-30 minutes of injection. This is the defining characteristic of GHRP-6 compared to other GHRPs.

Mitigation

Beneficial for bulking but problematic for cutting. Time doses strategically or use GHRP-2/Ipamorelin instead for cutting.

Cortisol Elevation

common
Severity
2.5/5

Higher ACTH and cortisol stimulation than GHRP-2, comparable to CRH stimulation.

Mitigation

May contribute to fatigue with chronic use. GHRP-2 or Ipamorelin are cleaner alternatives.

Prolactin Elevation

common
Severity
2.5/5

Higher prolactin increase than GHRP-2. Potential for decreased libido or gynecomastia with chronic elevation.

Mitigation

Monitor prolactin if using long-term. Usually not problematic at standard doses.

Water Retention/Bloating

common
Severity
2/5

More pronounced than GHRP-2. Often localized to abdominal region.

Mitigation

Usually resolves within 2 weeks. Reduce dose if problematic.

Injection Site Reactions

uncommon
Severity
1/5

Flushing, warmth, tingling, or numbness at injection site.

Mitigation

Rotate injection sites.

Headaches

uncommon
Severity
1.5/5

GH-related headaches reported occasionally.

Mitigation

Usually transient.

General Mitigation Strategies

The intense appetite stimulation is the primary consideration - beneficial for bulking but can derail cutting phases. Cortisol and prolactin elevation are higher than GHRP-2 or Ipamorelin, making GHRP-6 the least selective of the common GHRPs. Consider GHRP-2 for a cleaner profile with similar GH release.

Post Cycle Therapy (PCT)

✓PCT Not Required

Does not affect HPT axis. No PCT required.

How It Works

GHRP-6 binds to the GHS-R1a (ghrelin receptor) on pituitary somatotrophs, signalling through the Gq/phospholipase C - PKC pathway (not the cAMP/PKA pathway used by GHRH). It requires endogenous GHRH for maximal effect - Pandya et al. showed GHRP-6 alone produced a ~33.8 μg/L peak GH rise that fell to ~6.2 μg/L when endogenous GHRH was blocked with a GHRH antagonist. It also strongly stimulates appetite through central ghrelin receptor activation.

Fundamentals

Reference on the practices relevant to GHRP-6: how they are done and where they go wrong. Not a recommendation to use it.

Reconstitution & concentration math→

Turning this powder into a measured dose

Sterile technique & injection-site infection→

Avoiding abscesses and cellulitis

Bloodwork: what to measure and when→

The markers that matter here

Warning signs & when to seek care→

When to stop and get help

Common Stacks

  • GHRP-6 + Mod GRF 1-29 (CJC-1295 no DAC) - Synergistic GH release, the gold standard combo
  • GHRP-6 during bulking, switch to GHRP-2/Ipamorelin for cutting
  • GHRP-6 was the pharmacological reference compound for MK-677 (oral GH secretagogue) - "mechanistically indistinguishable" per its discovery paper

WADA Status

⛔Prohibited by WADA
Category: S2. Peptide Hormones, Growth Factors, Related Substances and Mimetics
In-Competition: ProhibitedOut-of-Competition: Prohibited

GHRP-6 is prohibited at all times under WADA category S2 as a growth hormone-releasing peptide (GHRP).

References

Last updated: July 18, 2026